Furnace



Aprii 7, 1925. 1,532,689

I J. FITZPATRICK FURNACE Filed June 27, 1923 LNVENTOR l ATTORNEYS eaeaaa A r. 7, i925.

s'rras JOHN nrrzrnrnron, or CINCINNATI, OHIO, AssIGNon T THE cnnnonunnum com rm, or NIAGARA FALLS, NEW YORK, A CORPORATION or PENNSYLVANIA.

FURNACE.

Application filed June 27, 1923. Serial No. 648,008.

To all whom it may concern:

Be it known that T, JOHN FITZPATRICK, a citizen of the United States, residing at Cincinnati, in the county of Hamilton and State of Ohio, have invented a new and useful Improvement in Furnaces, of which the following is a full, clear, and exact description.

This invention relates to furnaces, and particularly to combustion furnaces for the heating of materials or the smelting of ores while maintaining them out of contact with the combustion gases during their treatment.

I provide an enclosed heating chamber having a hearth adapted to-hold the materials to be heated, and a combustion chamber beneath the hearth and out of communication with the heating chamber.' The hearth is preferably constructed of silicon carbide, since this material has a high thermal conductivity, is mechanically strong, and is nonporous. The silicon carbide hearth is made thin and is supported by refractory posts or spacers from a sub-hearth, and the combustion gases are free to circulate between them.

Means for charging and discharging the material to and from the hearth are also provided. The hearth-may be rotary, or drag chains may be provided on a stationary hearth.

In the accompanying drawings illustrating the present preferred embodiment of my invention,-

Figure 1 is a sectional view in lan, taken on the line II of Figure 2, and

Figure 2 is a vertical section on the line HII of Figure 1; I

In the illustrated embodiment of my invention a circular hearth 2 made up of bonded slabs of silicon carbide forms the bottom of an enclosed material-heating chamber 3. The material to be treated is introduced adjacent the rim of the hearth 2 through a hopper 4 and a screw conveyor 5. Stationary scrapers 6 tend to move the material toward the center as the hearth is rotated. The hearth 2 is rotated by a central hollow shaft 7 extending outside the fur-. nace and driven from a power shaft 8 through gears 9. As the hearth revolves, the heat treated material moves toward the center and is finally discharged through the hollow shaft 7 The scrapers 6 are carried on an arni 10 and their position or inclina tion may be changed as desired to regulate the time any particular material remains in the furnace. The speed of rotation may also be changed to achieve the same result.-

A combustion chamber llis provided below the hearth 2' and is sealed ofi from the heating chamber 3 by a sand seal 12. The hearth 2 is'supported from a sub-hearth 13 by refractory posts 14:. The sub-hearth 13 comprises an upper refractorylayer 15 of fireclay or the like, a layer of insulating material 16, and a circular cast iron plate 17 supported on rollers 18. The hollow shaft 7 is protected by a refractory collar 19 between the hearth 2 and the subhearth 13.

The furnace is heated by a plurality of burners 20 using oil or gas as fuel. The combustion gases circulate freely between the hearth 2 and the sub-hearth 13 as they rotate and very effectively heat the material or ore being treated.

The waste gases pass out of the furnace through openings 21 in the sub-hearth 13 and adjacent the hollow shaft 7. These openings lead down through the-sub-hearth 13 and through thebase of the furnace to an annular flue 22, from which the gases are carried. to the chimney. A sand seal 23 is provided between the iron plate 17 and the base oithe furnace to insure proper flow of the products of combustion, and a water cooled bearing 24 is provided for the hollow shaft 7 to insure proper operation regardless of heat conditions.

I provide a furnace which is suitable for treating ores for recovering metals, for the heating treating of small metal parts, for the treatment of oil shale, and for many other useful urposes. The silicon carbide hearth and tie provision of a combustion space immediately therebelow insure high furnace efficiency and low operating cost. The furnace as a whole is simple in construction and not likely to get out of order.

While I have shown the preferred embodiment of my invention, it will be understood. that it is not limited thereto but may be otherwise embodied within the scope of the following claims.

I claim:

1. A. furnace including an enclosed material-heating chamber, a rotatafole hearth therefor adapted to hold the material to be heated and having a hollow shaft about the axis of which the hearth rotates, means for charging the hearth adjacent its edge, andmeans for discharging the hearth through the hollow shaft, substantially as described.

2. A furnace including an enclosed material-heating chamber,a rotatable hearth therefor adapted; to hold the material to be heated and having a hollow shaft about the axis of which the hearth rot-ates, means for chargingthe hearth. adjacent its edge, means for discharging the hearth through the hollow shaft, acombustion chamber below the hearth through which the hollow shaft projects, and means for maintaining the heating chamber out of communication with the combustion chamber, substantially as described.

3. A furnace including anenclosed material-heating chamber, a rotatable hearth therefor adapted to hold the material to be heated and having a hollow shaft about the 7 axis of which the hearth rotates, a supporting sub-hearthspaced from the hearth and rotatable with the same, means for-circulating a heating fluid between the hearth and 'the sub-hearth, means for taking the heat ing fluid from the furnace through the subhearth, and means for discharging the ihearth' through the hollow shaft, .substantially as described. 7 r

In testimony whereof I have hereunto set my hand. :7

J OHN FITZPATRICK. 

